MRI Postprocessing Helps to Detect Focal Cortical Dysplasia in Siblings

Abstract

Correspondence Neuroradiology Clinical IntroductionFocal cortical dysplasia (FCD) is a significant cause of medically refractory epilepsy and increasingly recognized in formerly cryptogenic cases. It is a malformation of cortical development (MCD) due to abnormal cell proliferation and/or abnormal cortical organization during pregnancy and can be classified according to histopathologic criteria with respect to changes in different stages of cortical development. The best correlation between histopathologic criteria, magnetic resonance image (MRI) findings and genetic findings are known for FCD of Taylor's balloon cell type [1,2]. MRI features of FCD include increased cortical thickness, abnormal gyral and sulcal contours, disturbed differentiation of the gray-white matter interface, and hyperintense signal in T2-weighted images [3]. However, in subtle cases, a correct diagnosis by visual evaluation of MRI alone remains difficult. There exist several image postprocessing strategies to facilitate lesion detection such as curvilinear reformatting of three-dimensional MRI [4,5], quantifying the regional distribution of gray and white matter [6], statistical parametric mapping [7], measuring the thickness of cerebral cortex [8], autoblock analysis [9], texture or morphometric analysis [10][11][12][13][14]. MRI postprocessing based on morphometric analysis helps to detect and to delineate FCD by generating new three-dimensional maps which characterize and highlight different features of FCD, i.e., abnormal thickness of the cortical ribbon, abnormal extension of gray matter into the white matter, and blurring of the graywhite matter junction [10][11][12]15]. In several forms of MCD such as lissencephaly, subcortical band heteroto-